However, the literature also contains some suggestions about the foundational significance of these models which might be interpreted as going beyond these operational claims. For example, ref [1]} suggests these models can be used `to establish an account of causality in quantum theory’s own terms, without assuming a separate realm of classical systems or measurement outcomes. The account provides its own answer to many of the basic questions concerning causality in a quantum universe.' The idea is that if we redefine `cause' in the quantum regime to refer to quantum causal models rather than classical ones, then we can after all have `causal explanations of quantum processes'[2]}. But some caution is required here - the fact that `quantum causal structure' offers a practically useful way of describing certain laboratory phenomena does not necessarily entail that it is providing a meaningful explanation of those phenomena. After all, `quantum causal structure' is not causation in the traditional sense, so even if one takes it that a traditional causal account is automatically explanatory, something more must be done before we can accept that this kind of structure is similarly explanatory. And since it is a truism that it is possible to give an operational description of laboratory procedures, the existence of such a description for some phenomenon should not be taken as revealing any deep fact about the phenomenon beyond the fact that it can be implemented in a laboratory. In particular, we caution that the use of quasi-causal concepts in operational descriptions of phenomena like the Bell correlations should not be allowed to obscure the very important point that the Bell correlations and other nonlocal phenomena do not exhibit causal order, which as we have seen in this article can be regarded as an important clue about the right way to understand the Bell correlations and how they relate to spacetime causal structure. This observation is entirely consistent with the claim that the Bell correlations can be embedded in a top-down `quantum causal model' describing the operational procedures needed to produce them: the point is simply that this kind of operational description does not necessarily tell us anything about the nature of the Bell correlations.
